Installations for reprocessing irradiated nuclear fuels have large so-called hot cells wherein processing components are accommodated. These cells are shielded with respect to radiation and contain frames known as racks in which the processing components are mounted.
Maintenance work inside the large-area radioactive cells has to be performed without personnel entering the cell. Maintenance work is therefore carried out by travelling remote handling apparatus. In this connection, the racks holding the processing components are placed along the walls of the hot cell in a modular configuration to facilitate remote handling. This makes it possible to exchange a complete rack or parts of a rack.
When a rack or a part thereof is exchanged, all the conduits which connect two racks directly with one another or are connected to conduits leading through the wall of the cell have to be separated by remote handling and reconnected when a new rack or new part thereof has been installed. It is necessary for whole sections of the conduits to be removed in order to enable the rack to be dismantled, since these sections of conduit would prevent a removal or an exchange of the rack.
Removable conduit interconnecting units or removable conduit members are therefore used which have connectable end flanges at the respective ends thereof. When conduits leading through the wall of the cell are connected to conduit connecting ends in the rack, each of the conduit interconnecting units are inserted between a stationary end flange of the conduit plate mounted on the wall of the cell and an end flange of a conduit connecting end of a processing apparatus arranged in the rack. The conduit interconnecting unit is coupled to these two end flanges.
Between these two stationary end flanges, there is a predetermined space into which the interchangeable or removable conduit member is inserted or from which it is removed. The flanges are joined together by known means such as clamping ring couplings or threaded fastener connections.
The conduit pieces to be coupled have to be brought together on center. Since guiding the conduit pieces together must be done by remote handling, there is a particular problem for the operator who monitors and performs the connecting process with aid of television; namely, just before the conduit members are brought together, only a poor view of the coupling location is available. This leads to frequent unsuccessful attempts to insert the interchangeable or removable conduit interconnecting member.